A DCOM error occurred trying to contact the remote computer. Access is denied.

Remote debugging uses Distributed Component Object Model (DCOM) to communicate between the local and remote computers in the following situations:

The debugger is set to Native Compatibility Mode or Managed Compatibility Mode is checked in the Tools > Options > Debugging page
You are debugging managed C++ (C++/CLI) code.
In older versions of Visual Studio, when Enable native Edit and Continue is checked in the Tools > Options > Debugging page
Some third party debugging scenarios

This error occurs when the Visual Studio process cannot authenticate itself (or the supplied credentials were deemed insufficient) to the remote debugger process over DCOM. One or more of the following workarounds might resolve the issue:
Turn off Native Compatibility Mode and Managed Compatibility Mode.
In older versions of Visual Studio, turn off Enable native Edit and Continue.
Reboot both computers.
If remote debugging requires entering credentials, check the option to save the credentials.

See also